At 11:05 PM 2/5/01 -0600, pat hayes wrote:
>That depends on what you mean by 'model' (and 'structure'). They are
>sufficient to *implement* any finite directed graph, indeed, in common
>with a host of alternative datastructuring primitives (eg LISP
>s-expressions based on dotted pairs). They are not so suitable for
>efficiently representing numerically indexed structures such as arrays and
>tables,
At this level, I don't think efficient representation is the prime goal. I
wouldn't use RDF to represent a matrix in an spatial computation
program. But it might be a convenient way to exchange the resulting
information.
>and they are only suitable for representing linguistic structures such as
>structured code or logical expressions if supplemented with some
>conventions for binding label names and indicating scope boundaries. (All
>of this is well-known, almost classical, in both the logic and programming
>communities and has been for about 40 years or more: I learned it at grad
>school and it was considered ancient lore way back then.)
Ah, yes! A topic in RDF that I hope to pursue with more energy, "real
soon now".
>Triplet structures have their uses, but the almost irrational passion
>revealed for them by members of the RDF community remind me of what
>happened when I once questioned Christian doctrine on a fundamentalist
>email list.
I'll not claim that RDF (including triples) is fundamentally "best" or
"universal" in any way. I have no such knowledge. From my perspective,
it's main advantage is that it exists, it has a community of activists,
certain simple things can be done simply, and it holds a promise of being
able to provide support to much more complex activities, albeit
sub-optimally in some cases.
There is a huge potential capability created by interoperability between
diverse systems. Common tools, common datasets, common memes allow folks
worldwide to work together to far greater effect. (Henry Thompson
introduced me to the memorable phrase "standing on the shoulders [of
others], not on their toes".) I think this is the great promise of RDF,
and when contributions from experienced thinkers in the field like yourself
help us to more clearly understand its limitations, that makes a stronger base.
I can imagine that one day, another technical proposal will come along that
is so superior that it blows away RDF. Even then, I believe the experience
with RDF will have been valuable. So for now, I'll try and design the best
systems I can based on RDF.
#g
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Graham Klyne
GK@NineByNine.org